There is appeal to being hated by everyone to the extent that it unites everyone under their hatred. Also even if you don't plan to take the option, the option being arbitrarily removed is infuriating. The makers of Mass Effect (still fuck those guys) said that vast majority players choose the Paragon option but they still kept the Renegade option because having that option is important. Let me ask you. Let's just imagine that you support the Legion in this one playthrough (shocking, I know). However you for some reason found out that Caesar is unkillable until the Second Battle at Hoover Dam just like how Ulfric Stormcloak was unkillable unless you progress the Legion side of the civil war quest. Will that knowledge upset you? BTW: I was thinking about how one of the solutions to the Yes-Man end game was to blow up the dam's generator making the NCR lose interest of the dam. I was thinking of having an ending with the Wild Wasteland Trait where the ending narration in the slides are replaced with incoherent swearing.